For FY13, we have used multi-dimensional NMR, X-ray crystallography, site-directed mutagenesis coupled with isothermal titration calorimetry to study how nucleosomes and histones are recognized by other proteins. We have determined the crystal structure of the CENP-C-CENP-A nucleosome complex and found a conserved mechanism for recognition of the centromeric nucleosome by the kinetochore protein CENP-C. We have built a structure model for the H1-nucleosome complex with residue-level information, which shows a unique orientation of H1 in the H1-nucleosome complex. In addition, we have investigated how the centromere-specific histone is recognized by its chaperone. We found that the centromere histone in budding yeast (Sc and Kl) has a partially unfolded conformation that is specifically recognized by the chaperone Scm3. We also solve the structure of histone variant H2A.Z in complex with the N-terminal region of the Swr1 subunit of the SWR1 remoldeler. Our results show that Swr1 deliver the H2A.Z-H2B by a chaperone mechanism.